Instruments such as endoscopes and borescopes are used to allow a visual inspection of locations which are not readily accessible. For example, endoscopes are used in medical applications to provide a view of an area within a patient's body. Whether employed for medical or other applications, the instrument typically includes an elongated shaft of relatively small diameter extending from a handle to a distal end. An imaging or viewing arrangement is included with the instrument to allow a user to obtain a view from the shaft distal end. This arrangement may include a system of lenses and a light conduit through the shaft to direct an image from the distal end to an eyepiece associated with the instrument handle. Alternatively, the imaging or viewing arrangement may include an electronic imaging device at the distal end of the instrument shaft. Such an electronic imaging device collects image data and communicates that data through the shaft and handle ultimately to a processing system that assembles the data to produce an image displayed on a suitable display device.
Depending upon the procedure for which the instrument is used, it may be necessary for the operator to view a relatively large area, or view a relatively small area from different angles. In a medical procedure for example, the operator may desire to view a location which is larger than the field of view of the imaging collecting arrangement of the endoscope or view a location from different angles. In these situations it has been necessary for the endoscope operator to move the distal end of the endoscope in an effort to provide the desired views, and sometimes move the distal end repeatedly in given area.
Endoscopes have been developed to give the operator the ability to adjust viewing angle. U.S. Patent Application Publication No. 2015/0238068 discloses an endoscope having an objective lens and prism that is mounted on a pivotable structure at the distal end of the endoscope. This endoscope, however, allows rotation to only one side of the device. Thus the endoscope had to be repositioned in the area of the procedure in order to view a location on the opposite side of the endoscope shaft. U.S. Patent Application Publication No. 2014/0012080 shows another endoscope with an image collecting part which may be tilted to one side of the endoscope at the distal end. This arrangement also requires the endoscope distal end to be repositioned to obtain views of areas on the opposite side of the endoscope shaft (that is, opposite the side to which the image collecting device is tilted at a given point in time).
U.S. Pat. No. 6,371,909 discloses an endoscope having an imaging assembly mounted in the distal end of the endoscope so as to allow articulation about two axes. This two-axis articulation facilitates different viewing angles through a transparent cover at the distal end of the endoscope. The articulating arrangement disclosed in U.S. Pat. No. 6,371,909, however, greatly constrained the nature and size of the imaging device which could be employed for a given diameter endoscope distal end. Also, the distal end of the endoscope in U.S. Pat. No. 6,371,909 had to be repositioned to provide a view of any area other than the area at the far distal tip of the endoscope shaft.
There remains a need in the art to provide an optical instrument such as an endoscope or borescope that allows the imaging device to be adjusted so that different views can be obtained without having to move the instrument distal end, or at least limiting the amount to which the distal end must be moved in a given procedure.